package v2ch02.regex;

import java.util.*;
import java.util.regex.*;

/**
 * This program tests regular expression matching. Enter a pattern and strings to match,
 * or hit Cancel to exit. If the pattern contains groups, the group boundaries are displayed
 * in the match.
 *
 * @author Cay Horstmann
 * @version 1.02 2012-06-02
 */
public class RegexTest {
	public static void main(String[] args) throws PatternSyntaxException {
		Scanner in = new Scanner(System.in);
		System.out.println("Enter pattern: ");
		String patternString = in.nextLine();
		
		Pattern pattern = Pattern.compile(patternString);
		
		while (true) {
			System.out.println("Enter string to match: ");
			String input = in.nextLine();
			if (input == null || input.equals("")) return;
			Matcher matcher = pattern.matcher(input);
			if (matcher.matches()) {
				System.out.println("Match");
				int g = matcher.groupCount();
				if (g > 0) {
					for (int i = 0; i < input.length(); i++) {
						// Print any empty groups
						for (int j = 1; j <= g; j++)
							if (i == matcher.start(j) && i == matcher.end(j))
								System.out.print("()");
						// Print ( for non-empty groups starting here
						for (int j = 1; j <= g; j++)
							if (i == matcher.start(j) && i != matcher.end(j))
								System.out.print('(');
						System.out.print(input.charAt(i));
						// Print ) for non-empty groups ending here
						for (int j = 1; j <= g; j++)
							if (i + 1 != matcher.start(j) && i + 1 == matcher.end(j))
								System.out.print(')');
					}
					System.out.println();
				}
			} else
				System.out.println("No match");
		}
	}
}
